Rejuvenation of wells and other ground-water collecting devices

ABSTRACT

A drilled well of deficient performance due to accumulation of scales on the water-intake parts of its well pipe is rejuvenated at low cost by inserting a cleaning pipe of smaller diameter through the well pipe to supply concurrently to the water-intake parts an aqueous solution of a harmless washing agent and highpressure air, which produce a cooperatively combined agitation action by which the scales are chemically dissolved, loosened, and washed off and can be subsequently removed by pumping through the well pipe. The air and solution are delivered from respective supply pumps and supplied through a mixer to the cleaning pipe to be ejected with high energy through a vaned turbine wheel at the lower end of the cleaning pipe.

United States Patent [191 Yokoyama 1 REJUVENATION OF WELLS AND OTHERGROUND-WATER COLLECTING DEVICES [75] lnventor: Kashimi Yokoyama,Hiroshima,

Japan [73] Assignee: Suiri Kogyo Kahushiki Kaisha, Hiroshima, Japan [22]Filed: Mar. 23, 1971 [21] Appl. No.: 127,124

[30] Foreign Application Priority Data Dec. 28, 1970 Japan ..45/119633[52 us. Cl ..166/312 [51] ..E2lb 21/00 [58] Field of Search ..166/312,305 R, 222, 166/223, 67

[56] References Cited UNITED STATES PATENTS 2,768,694 10/1956 Moll.,l66/312 X 2,740,476 4/1956 DAudiffret ..166/305 R 2,126,575 8/1938Renney ..166/305 R X [1 1] 3,72%,054 45] Apr. 24, 1973 PrimaryExaminerRobert L. Wolfe AtmrneyHolman & Stern l 5 7 ABSTRACT A drilledwell of deficient performance due to accumulation of scales on thewater-intake parts of its well pipe is rejuvenated at low cost byinserting a cleaning pipe of smaller diameter through the well pipe tosupply concurrently to the water-intake parts an aqueous solution of aharmless washing agent and highpressure air, which produce acooperatively combined agitation action by which the scales arechemically dissolved, loosened, and washed off and can be subsequentlyremoved by pumping through the well pipe. The air and solution aredelivered from respective supplypumps and supplied through a mixer tothe cleaning pipe to be ejected with high energy through a vaned turbinewheel at the lower end of the cleaning pipe.

3 Claims, 13 Drawing Figures Patented April 24, 1973 5 Sheets-Sheet 1FIG.

Patented April 24, 1973 3,729,054

5 Sheets-Sheet 2 Patented April 24, 1973 3,729,054

5 Sheets- Swat 5 FIG-7(0) FIG.7(b)

Patented April 24,1973 3,729,054

5 Sheets-Sheet 4 FIGBW TO PUMP ooooo oooo o 1 WATER Patented April 24, 1973 5 Sheets-Sheet .5

F I G. lO(b) REJUVENATION OF WELLS AND OTHER GROUND-WATER COLLECTINGDEVICES BACKGROUND OF THE INVENTION This invention relates generally towells and more particularly to a new and advanced process and apparatusfor rejuvenating or reconditioning wells and other devices for obtainingground water which are deficient in performance because of accumulationof scales on their water-intake parts. The invention is particularlyeffective and useful in rejuvenating water wells for obtaining potablewater, industrial water, and water from springs such as hot springs andcold mineral-water springs.

Among the facilities known from the past for obtaining water from watersources for water pipeline service in cities, towns, and villages and inenterprises of various kinds and sizes, the most widely used facilitiesfor obtaining ground water and intermediate infiltration water andriver-bed water have been drilled wells (known also as bores, borings,tube wells, and bore-hole wells) and dug wells each lined with a sunkencasing such as a so-called Hume concrete pipe with a perforated bottompart or adrilled well pipe provided with a strainer at its lower end.

As is known, the operation including that of these wells in obtainingwater comprises collecting the source water flowing underground, pumpingthis water as collected into a reservoir once, and purifying this waterby a chemical solution treatment, chlorine pretreatment, or any ofvarious filtration methods to remove iron, manganese, turbidity, andvarious kinds of coagulated impurities thereby to render the water intoclear potable water or industrial water.

Since it has not been possible to carry out underground thispurification and treatment of the source water, scales due to impuritiescontained in the source water are deposited and accumulate on thewater-intake parts of these facilities for obtaining source water and inclosely neighboring regions, whereby the performances of thesefacilities, which entail high manufacturing and installation costs, dropyear by year. The present state of the art is such that these facilitiesmust for this reason be abandoned or reinstalled at high cost after onlya relatively short time of a few years to ten years or somewhat more.

SUMMARY OF THE INVENTION It is an object of the present invention toovercome the above described difficulty by utilizing certain findings Ihave made as described hereinafter.

More specifically, an object of the invention is to provide a simple andlow-cost process for removing accumulated scales as described abovewhereby devices for obtaining ground water of lowered performance due toscales can be economically rejunevated.

According to the present invention, briefly summarized, there isprovided a process for removing such scales which is characterized bythe steps of supplying concurrently an aqueous solution of a harmlesswashing agent and air at a high pressure to and through the water-intakeparts of the water-obtaining device thereby to cause disintegration,loosening, and washing off of the scales by the cooperatively combinedagitation action of the solution and air and thereafter operating thedevice to pump and remove water containing the scales thus washed off.

According to this invention in another aspect thereof, there is providedan apparatus for carrying out the above stated process, this apparatusbeing characterized by the combination of first and second pumps fordelivery, respectively, of the wash solution and the high-pressure air,mixing means for mixing the solution and air thus delivered to produce amixture thereof, a pipe connected at one end to the mixing means andfunctioning to supply the mixture into the water-obtaining device, andejection means connected to the other end of the pipe and operating toeject the mixture with great energy against the water-intake partsthereby to cause the disintegration, loosening, and washing off of thescales.

The nature, principle, details, and utility of the invention will bemore clearly apparent from the following detailed description withrespect to preferred embodiments of the invention when read inconjunction with-the accompanying drawings, in which the same orequivalent parts are designated by the same reference numerals andcharacters.

I BRIEF DESCRIPTION OF THE DRAWINGS In the drawings:

FIG. 1 is a diagrammatic elevation showing the essential parts andorganization of a drilled well for obtaining ground water;

FIGS. 2 and 3 are, respectively, a fragmentary elevation and a sectionalplan view indicating the state of deposition of scales on thewater-intake parts at the lower part of the well pipe of the well shownin FIG. 1;

FIGS. 4, 5 and 6 are views similar to FIGS. 1, 2, and 3, respectively,indicating the disintegration and washing off of scales around the outerperiphery of a well pipe by the cooperatively combined agitation of anaqueous solution and high-pressure air in accordance I with theinvention;

FIGS. 7(a) and 7(b) are, respectively, a diagrammatic elevation and afragmentary plan view indicating the state of deposition of scalesaround a gallery or adit extending horizontally from a dug well;

FIGS. 8(a) and 8(b) are respectively a diagrammatic elevation and afragmentary plan view indicating the state of deposition of scales onthe bottom periphery of a dug well,

FIG. 9 is a diagrammatic elevation, partly in section and with parts cutaway, illustrating a specific example of apparatus according to theinvention for carrying out the process thereof; and

FIGS. 10(a) and 10(b) are, respectively, a relatively enlarged elevationin vertical section and a plan view of a vaned turbine wheel rotatablysupported on the lower end of the pipe for supplying the wash solutionand high-pressure air.

DETAILED DESCRIPTION As a result of observations of actual phenomena inthe development of the present invention, 1 have verified that the causeof the coagulation, deposition and accumulation of scale on the outerperiphery of a well pipe is as follows.

When the quantity of the source water passing through a strainer 3 atthe bottom end part of a drilled well pipe I, for example, as shown inFIG. 1 decreases, the dynamic water-level drop on the suction side ofpump 4 as indicated by curve 7 due to a water-level drop 6 cause asubstantial lowering of the pump performance, and the concentration ofimpurity substances in the source water existing stagmently around theouter periphery of the strainer pipe 3 progressively increases, theimpurities adhering and accumulating with the highest concentrationthereof around the outer periphery of the well pipe and becomingprogressively less concentrated in the radially outward direction with aconical distribution pattern as indicated in FIGS. 1, 2, and 3.

In accordance with the present invention, a waterobtaining device in theabove described state of contamination by scales is rejuvenated in themanner described hereinbelow with respect to a drilled well constitutinga specific example.

The conventional pump 4 is disconnected from the upper end of the wellpipe 1, and a combination of a pump 8 for supplying an aqueous solutionofa harmless washing agent and an air-supplying device 9 for supplyingair at high pressure is installed for intercoupled operation at theupper end of the well pipe I as illustrated by one example as shown inFIG. 4, and a pipe 10 is inserted through the well pipe 1 to supply thewash solution and high-pressure air to the bottom end ofthe well pipe I.

As a result, the oxygen within the high-pressure air and the solutionproduce a cooperatively combined agitation action by which the depositedscale 5 is disintegrated and washed off.

Thereafter, the conventional pump 4 is reconnected to the upper end ofthe well pipe 1 and operated for a period sufficient to pump out allcontaminated water resulting from the above described rejuvenationprocess. The well thus reconditioned can then be operated in theordinary manner with a performance higher than that prior to therejuvenation process.

In accordance with this invention, there is further provided anapparatus for carrying out the above described process. In a specificexample of the apparatus, as illustrated in FIGS. 9 and 10, theaforementioned pipe 10 is provided at its lower end with a vaned wheel25 rotatably supported by the pipe 10 in a manner permitting freerotation of the wheel about a vertical axis. The lower end of the pipe10 communicates with the interior of the wheel 25 through a centralinlet port at the upper part of the wheel. The interior of the wheel isprovided with vanes 25a and has a peripheral outlet opening 26. Themaximum diameter of the vaned wheel is less than the inner diameter ofawell pipe 1 which is to be cleared, and means (not shown) are providedto center the wheel 25 with respect to the axis of the well pipe 1thereby to prevent contact therebetween.

The pipe 10 with the vaned wheel 25 is inserted into a well pipe I afterthe pump device 4 has been disconnected, the upper end of the pipe 10being connected by way of a flexible pipe 27 to a supply device 32 forsupplying a wash liquid and high-pressure air. This supply device 32comprises essentially a high-pressure air pump 33, a wash-liquid supplypump 34, and a mixer 35 connected to the delivery outlets of the airpump 33 and wash-liquid pump 34 and operating to mix the air and washliquid and to deliver the resulting mixture to the pipe 10 through theflexible pipe 27. The pumps 33 and 34 are powered by respective motivemeans 330 and 34a.

The apparatus of the above described organization according to theinvention is used and operates in the following manner. The pipe 10 isfirst installed within the well pipe 1 at a depth such that the variedwheel 25 5 is positioned at a level in the neighborhood of the strainer3. The motive power means 330 and 34a are then started to operate thepumps 33 and 34. Highpressure air delivered by the air pump 33 and thewash liquid delivered by the wash-liquid pump 34 are thereupon mixedwithin the mixer 35, and the resulting mixture is supplied through thepipe 10 and enters the vaned wheel 25.

The mixture thus supplied into the vaned wheel 25 causes the wheel torotate at a high speed depending on the kinetic and pressure energy ofthe mixture itself. The wash liquid mixed up completely with the air, isthereby ejected with great force toward the inner wall surface of thestrainer 3 by centrifugal force due to the rotation of the vaned wheel25 and disintegrates and washes off scale in cooperation with the oxygenwithin air as described hereinbefore.

This washing operation is preferably carried out as the pipe 10 isreciprocated up and down so that the vaned wheel 25 traverses throughthe total length of the strainer 3, that is, between levels 28 and 29indicated in FIG. 9. By this procedure the scale adhering to thestrainer and its neighborhood can be throughly removed.

While the invention has been described above with respect to one exampleof application thereof to a drilled well, its application is not solimited but includes that to a dug well with a casing having aperforated bottom part as illustrated in FIGS. 8(a) and 8(b), in whichthe accumulation of scales is designated by reference numeral 13.Another example of application of the invention is that to a dug wellwith a perforated gallery or adit extending horizontally from the lowerpart thereof through a region in the river bed of a river 12 as shown inFIG. 7(a). In this case, the scale accumulation assumes a distributionas indicated at l 1 in FIG. 7(b).

A well or like water-obtaining facility contaminated by an accumulationof scales can be thus rejuvenated in accordance with the invention at acost which has been estimated to be from one-third to one-fifth the costof installing a new facility.

I claim:

1. Apparatus for removing scales adhering to waterintake parts of aground-water collecting well comprising, in combination, a first pumpfor delivering an aqueous solution of a harmless washing agent, a secondpump for delivering high-pressure air, means for mixing the aqueoussolution and air thus delivered to produce a mixture thereof, a pipeconnected at one end to said mixing means and extending downward throughthe well to terminate at the other end near the water-intake part tosupply the mixture into the ground-water collecting well, and a vanedturbine wheel rotatably supported on the other end of the pipe forrotation about a vertical axis by the energy of said mixture suppliedtherein to through the pipe and having a central inlet and a peripheraloutlet for flow of the mixture and radial ejection thereof undercentrifugal force against the scales, the ejection of the mixturecausing disintegration, loosening, and washing off of the scales by thecooperatively combined agitation action of the washing agent and the airand by chemical action of the washing agent against the scales.

2. The apparatus as claimed in claim 1 in which said mixing meansincludes means for spraying the aqueous solution into the flow of thehigh pressure air.

3. The apparatus as claimed in claim 1 in which said pipe and hence saidturbine wheel are reciprocable up 5 and down along the water-intake partof the well.

1. Apparatus for removing scales adhering to water-intake parts of aground-water collecting well comprising, in combination, a first pumpfor delivering an aqueous solution of a harmless washing agent, a secondpump for delivering high-pressure air, means for mixing the aqueoussolution and air thus delivered to produce a mixture thereof, a pipeconnected at one end to said mixing means and extending downward throughthe well to terminate at the other end near the water-intake part tosupply the mixture into the ground-water collecting well, and a vanedturbine wheel rotatably supported on the other end of the pipe forrotation about a vertical axis by the energy of said mixture suppliedtherein to through the pipe and having a central inlet and a peripheraloutlet for flow of the mixture and radial ejection thereof undercentrifugal force against the scales, the ejection of the mixturecausing disintegration, loosening, and washing off of the scales by thecooperatively combined agitation action of the washing agent and the airand by chemical action of the washing agent against the scales.
 2. Theapparatus as claimed in claim 1 in which said mixing means includesmeans for spraying the aqueous solution into the flow of the highpressure air.
 3. The apparatus as claimed in claim 1 in which said pipeand hence said turbine wheel are reciprocable up and down along thewater-intake part of the well.